A nanny who worked at the resort where Madeleine McCann disappeared has told detectives she saw a man lurking outside the family's apartment.

The woman contacted the McCanns' private detective agency to say the dark-haired man hid in bushes near the flat where she was baby-sitting for a six-year-old boy.

The incident happened in the summer of 2006, a year before Madeleine disappeared.

The former Ocean Club worker reported it to British police in June this year, after she heard that Madeleine was missing.

But she has not been questioned by Portuguese police, even though her account would support Kate and Gerry McCann's fear that their daughter was targeted by an abductor who might have spied on the family.

The theory would explain how an abductor was able to target Madeleine, knowing that she was alone in the flat with her two-year-old brother and sister, and that their parents were only checking on them every 30 minutes.

The ex-nanny told the Barcelona-based detective agency Metodo 3 that she was babysitting for the six-year-old boy in the same apartment used by the McCann family in Praia da Luz in May.

While she could not be more specific about the date, she said she thought it was a Thursday night - the same night Madeleine vanished - because it was "tennis night" at the resort and the boy's parents had gone off to play and left her with their son.

Mr and Mrs McCann, both 39, also played tennis during the afternoon of May 3, hours before they left their three children alone in the two-bedroom apartment while they went out for dinner nearby.

The nanny told private detectives she went outside the apartment because she received a phone call from her bosses to say there was a problem with rats, according to the Spanish newspaper El Mundo.

It reported: "For that reason, she left the flat briefly. Once outside, she saw something move in the darkness near to the apartment and initially thought it was a rodent.

"To her surprise she then saw a man's shoe. She shouted and the man ran out from the shadows and simply shouted, 'No, no' and fled before the holiday complex's emergency lights came on."

The nanny told resort managers he was aged 25 to 35 and looked Portuguese, and said he wore light-coloured trousers and a blue checked shirt.

A friend of the McCanns, Jane Tanner, has told police she saw a man walking away from the family's apartment on the night Madeleine disappeared, carrying a child in his arms.

She said he was dark-haired, about 35 years old and about 5ft 8in or 5ft 9ins tall, and wore a dark jacket and light beige trousers - a description which bears striking similarities to the man described by the nanny.

El Mundo said the nanny was believed to have called the 24-hour hotline last week. She worked at the Ocean Club for six months before leaving last October.

McCann family spokesman Clarence Mitchell said: "I believe this young woman did contact UK police before ringing the hotline.

"This nanny's evidence backs up what we have always said, that Madeleine was taken from her bed by an abductor."

A former Mark Warner nanny, Charlotte Pennington, said she was told about reports of a man hanging around the resort when she started work at the Ocean Club this year.

She said: "I did know that a complaint had been made. We were told about it when we arrived.

"We were told we shouldn't walk around by ourselves, and that we should lock our apartments because there had been some break-ins. They told us not to tell the guests."

Mark Warner refused to comment because of the ongoing police investigation.